- IAWA Small Collections, 1907/20133
- IAWA: International Archive of Women in Architecture Records, 1967/2013, bulk 1985/20081
- Ignorance Club collection, 1908/20242
- Independent Order of Odd Fellows. Olean Lodge No. 471 (Olean, N.Y.) Records, 1920/1956, bulk 1920/19251
- Independent Order of Odd Fellows. St. Albans Lodge, No. 31 (St. Albans, Vt.) Minute Book, 1917/19322
- Independent Order of St. Luke Records, 1877/197012
- Inge Horton Architectural Collection, 1964/1999110
- Ingleside Book Club Records, 1923/20231
- Institute for the History of Technology and Industrial Archaeology Records, 1875/2005, bulk 1980/200551
- Institute for the History of Technology and Industrial Archaeology, Records regarding Blair Mountain, 1906/1992, bulk 1990/19921
- Instructive Visiting Nurses Association records, 1902/199914
- Intercollegiate Athletics records, 19202
- Internal Library Records, 1923/20239
- International Association for Identification Records, 1842/2012, bulk 1910/195975
- International Order of Odd Fellows, Lodge 134, Ledgers, 1892/19281